Ball



Se t. 16, 1924. 1,509,025

J. w. PATTERSON BALL I Filed March 22 1920 maven/E03:

pmfiicrsam;

Patented Sept. 16, 1924.

UNITED' STATES PATENT JOHN W. PATTERSON, OF NEW HAVEN, CONNECTICUT. ASSIGNOR TO THE SEAMLESS V RUBBER COMPANY, INC., OF NEWCEAVEN, CONNECTICUT, A CORPORATION OF MASSACHUSETTS.

BALL.

Application filedMarch 22, 1920. Serial No. 367,729.

To all whom it may concern Be it known that I, JOHN W. PA'rrERsoN, a citizen of the Unitedstates, and a resident of New Haven, county of New Haven and State of Connecticut, have invented an Improvement in Balls, of which the following description, in connection with th accompanying drawings, is a specification, like characters on the drawings representing like parts. v

This invention relates to hollow balls and while not limited thereto finds particular application to tennis balls and especially to so-called unstitched tennis balls which are covered by sections of felt which are cc mentedthereto but which are not sewn to gether along their ed es.

The principles umirlying'my invention may be readily understood from the following description of an example thereof illustrated in the accompanying drawings,

I wherein Fig. 1 is a ball; and 1 Fig. 2 is a progressively broken" plan of the material used in making the same.

As an example of my invention I have herein shown an unstitched tennis ball embodying a hollow inflated center?) covered by separate sections of felt 5 and 7 suitably cemented thereto but inthe present instance, since an unstitched ball is shown, not sewn together along the meeting edges 9 of the sections. l

The ball center 3 may be constructed in accordance with any suitable known method, conveniently by vulcanizing together lune shaped sections. 'Such sectionsmay be. cut. from a suitable sheet of stock of which the preferred form is illustratedin Fig. 2. I have there shown a sheet of stock comprising twothicknesses 11 and 13 of rubbercomposition which may be similar to that at present commonly utilized for ball centers, being loaded in a manner well known in the art with zinc oxide, magnesia or the like to make it sufliciently hard and tough. Sheets of rubber have a certain grain due to their passage through the calendars and I have erein indicated by shading that the grain of the layer 13 is placed transversely of the grain of the layerfll so that the two cross.

partly broken elevation ofja The two sheets 11 and Bare unitedby a thin layer of pure black gum or gum rubber 15 without loading material of any kind.

OFFICE.

The thickness of the composite sheet may be substantially the same as the thickness of the stock usually employed for similar. ball centers.

As shown in Fig.- 1 the ball center 3 constructed from stock of this nature is a laminated structure comprising inner and outer layers of rubber composition with an inter mediate layer of pure black gum. The ball center 3 is suitably inflated in the case of the tennis ball and the crossing of the grain in the two layers in itself minimizes leaks due to porosity of the rubber'and the intermediate film" 15 of gum acts effectually to stop such leakages. a

The structure'also provides a ball; more durable and less likely to. break in use.

As these qualities of durability are most apparent at the joining line 9 it will conduce to brevity to refer to them as they are made stitched tennis ball more particularly, the center is subject. to bending strains along the line where the sections join. Elsewhere it is supported and the strains are distributed by the covering material and in the case of a stitched ball the stitches form a brace between the sections In the unstitched. ball, however, the joining line 9 of the sections forms a sort of hinge and it is found that balls will fail by splitting at this line." A laminated centeras here 16 manifest at that point. In the case of an unshown is obviously of greater flexibility I than one made in a single piece and particu larly this is' true in the vpresent instance because the layers 11 and Bean move more -or less' independently one of another due to their being joined by the highly yielding film of pure rubber 15. The presence of this highly flexible layer of material provides a hinging'action at the joint 9. which prevents the center from breaking. Further -more,'when two permanently united layers with crossed grain are used the ball is not likely to split because a, tear cannot start and continue through the two layers because a split tending to follow the grain of one will be across the grain of the other so that while a local break may occur'the ball 'of a center forme cannot be readily ripped open as in the case of a single layer of material.

The use of two layers with crossed grain equ'alizes the resistance to inflating pressure in such manner that the ball center when readily visible to the eye and this defect 1s,

in the course of time.

of coursefpresent in less degree at lower pressures. On the other hand the ball center constructed of a plurality of thickmesses with the grain crossed is perfectly round. v I

Inconstructingtennis balls the centers are usually given a preliminary inflation during vulcanization by means of ammonium carbonate which is decomposed by the heat of vulcanization and inflates the cured center. A decomposition product is ammonia which isv retained within the ball center and has a deteriorating effect on the same In the present ex+ ample of the .invention the layer 15 of gum proofs the center and protects the layer 13 from the ammonia which cannot eat through and destroy the integrity of the ball as a whole.

Having thus described in detail the particular form of my invention shown b way of 855 example in the accompanying rawings,

aeoaoae llowing and an intermediate layer of sott -substantially sulphur-free gum rubber.

3. An unstitched. tennis ball comprising a center having unjoined covering sections secured thereto, said center comprising two layers of tough rubber composition and an intermediate layer of soft substantially sulphur-free um rubber.

'4. An unstitched tennis ball. comprising a center having unjoined covering sections secured thereto, said center comprising two layers of tough rubber composition with the grain thereof relatively crossed and an intermediate layer of soft substantially sulphur-free gum rubber.

5. An inflated ball having a wall comprising a thickness of tough rubber composition p'roofed with a layer of pure substantially sulphur-free gum rubber.

ln testlmony whereof l have signed my name to this specification.-

JOHN W. PATTERSON 

